Conventionally, various kinds of integrated ignition apparatuses were proposed. In the ignition apparatus described in EP 0 907 019 A2, a stem of a plug section contacts a high voltage terminal of a coil section. However, in case that the stem is connected with the high voltage terminal by screwing or crimping, the connection between the stem and the high voltage terminal is apt to be disconnected due to vibration, causing failure in electric conduction.